I was mining one day, and found it annoying that I didn't know what time it was on the surface. Since carrying a clock around is inconvenient, (especially early game before I have gold) I decided to make a simple HUD element to fix it. The HUD shows the current progress through the day or night, and can be toggled on or off.
Mod Spotlights:
Modpack Policy: Clock HUD may by used in any modpack, public or private, without my explicit permission. You are required to remove Clock HUD from your modpack at my request.
Source code can be found on Github. This project is licensed under GPL.